<!DOCTYPE html>
<html>
	<head>
		<meta charset="UTF-8">
		<title>shengdanshu</title>
	</head>
	<style type="text/css">
		div{
			width: 200px;
			height: 100px;
		}
		.a1{
			width:0px;
			height:0px;
			border-left: 100px solid transparent;
			border-right: 100px solid transparent;
			border-bottom: 100px solid red;
		}
		.a2{
			width:0px;
			height:0px;
			border-left: 100px solid transparent;
			border-right: 100px solid transparent;
			border-bottom: 100px solid green;
		}
		.a3{
			width:0px;
			height:0px;
			border-left: 100px solid transparent;
			border-right: 100px solid transparent;
			border-bottom: 100px solid yellow;
		}
		.a4{
			width: 80px;
			height: 200px;
			position: relative;
			left: 60px;
			border: 2px solid blue;
			background-color: goldenrod;
		}
	</style>
	<body>
		<div class="a1"></div>
		<div class="a2"></div>
		<div class="a3"></div>
		<div class="a4"></div>
	</body>
</html>
